What a chemical dosing set does on site
A chemical dosing set is used to add treatment chemicals into a boiler, feedwater line, hot water circuit or calorifier at a controlled rate. On steam plant, that means better control over oxygen scavengers, pH adjusters, sludge conditioners and phosphate treatment where required. On hot water systems, it helps manage corrosion and keeps strainers, pumps and heat exchangers cleaner for longer.
The set normally includes a tank, dosing pump, suction strainer, discharge tubing, non return valves and basic control gear. Some sites only need a simple manual unit for low duty work. Others need a timed or level linked arrangement tied into the plant controls. The right setup depends on water quality, daily run hours, chemical type and how often the plant is under load. In Gauteng factories, schools, laundries and hospitals, dosing often has to cope with long operating hours and load shedding starts that can change boiler conditions quite quickly.
Common sizes and build options
Ai-TEC supplies chemical dosing sets in compact single pump units and larger twin pump arrangements for higher duty applications. Tank sizes are selected to suit the chemical and the frequency of refilling, with common volumes ranging from 25 litres up to 500 litres or more for busy plant rooms. Skid mounted layouts are available when floor space is tight, and wall mounted frames can be used for smaller systems.
Materials are chosen for the chemical being dosed and the site conditions. Coastal humidity is not usually a problem in Gauteng, but many plants still need UV resistant pipework, corrosion resistant fittings and secure mounting where vibration is present. If the dosing point is in a hot, dirty or restricted plant room, the system must be set up so operators can inspect it without moving other plant around.
- Single pump or twin pump configuration
- Manual, timed or level linked control
- Polyethylene or chemical resistant tank options
- Flow range matched to boiler size and make up water demand
- Fixed skid or wall mounted installation
Where dosing sets suit best
These sets suit commercial and industrial sites that rely on steady water treatment control. That includes boiler houses, laundry plants, abattoirs, food processing lines, hospitals, factories, schools, apartment complexes and municipal facilities. They are also useful on calorifier systems where scale build-up can reduce heat transfer and push energy use higher.
For steam plant, correct dosing helps protect tube surfaces, steam quality and downstream equipment. For hot water circuits, it helps reduce corrosion inside heaters and associated pipework. When a site has changing water supply quality, borehole water, or a softener that is not performing properly, chemical dosing becomes part of the wider treatment plan rather than a stand alone fix.
- Steam boilers with regular blowdown and make up water changes
- Hot water plant with calorifiers and circulation loops
- Sites running 24 hour production or shift work
- Plants that need tighter control after maintenance or refurbishment
Installation, utilities and space requirements
Most dosing sets need a level surface, safe access and a sensible route to the injection point. We usually look at the plant layout first, then confirm where the chemical tank can sit without interfering with walkways, valves or drainage. If the system is near a boiler, clearances for maintenance matter as much as the pump size.
Power needs are usually light, often standard single phase supply for small and medium units, with control wiring to a timer, level switch or plant panel where specified. Some arrangements only need a basic plug in supply, while others require proper isolators, cable glands and local control protection. If the dosing system is linked to existing plant controls, we also check interlocks so the pump does not run dry or dose into a shut line.
There is no gas supply requirement for the dosing set itself, but the surrounding plant room conditions matter. Heat, poor ventilation, vibration and chemical storage rules all affect the final setup. On sites in Boksburg, Kempton Park and Germiston we often find that the best result comes from a short pipe run, a clean mounting point and easy refilling access rather than a complicated layout that gets ignored after commissioning.
Care, servicing and water treatment support
Like any plant item, a dosing set works best when it is checked before it gives trouble. Pumps should be inspected for leaks, seals and output drift. Tanks need to be kept clean and clearly labelled. Strainers and injection points should be checked for blockages, especially where chemicals can crystallise or where the water quality changes after municipal work or heavy rain.
Ai-TEC supports dosing sets as part of wider boiler and hot water maintenance. That can include annual inspections, combustion tuning, water treatment support and emergency callouts when the plant is already under pressure. If a dosing pump stops feeding correctly, the effect can show up later as scale, poor test readings or corrosion in the system. Catching it early saves time and keeps the plant cleaner.
- Check pump delivery rate at set intervals
- Inspect suction lines, foot valves and injection non returns
- Keep chemical tanks covered and labelled
- Record test results and refill dates
- Flush lines after long shutdowns or chemical changes
What to confirm before you order
Before ordering, it helps to know exactly what the plant needs to achieve. A dosing set must match the chemistry, the flow rate and the operating pressure of the system. The wrong pump size can underfeed or overfeed, and both cause problems. We also need to know whether the set is for boiler feedwater, hot water circulation, or a separate treatment tank.
Useful details include the duty, the temperature, available power, floor space, chemical type and whether the unit must be portable or fixed. If the site has a softener, degasser, blowdown arrangement or existing water treatment programme, share that too. For plants in Pretoria, Midrand or Sandton with managed buildings, access times and shutdown windows can be just as important as the technical data.
When Ai-TEC quotes a chemical dosing set, we try to confirm the practical details upfront so the system arrives ready for the site instead of needing rework after delivery. That means fewer delays, less down time and a neater installation from the start.
Key facts
| Product type | Chemical dosing sets for steam and hot water plant |
|---|---|
| Typical tank sizes | 25 L, 50 L, 100 L, 250 L, 500 L plus |
| Pump options | Single or twin pump, manual or automatic control |
| Duty range | Light commercial to industrial plant |
| Utilities | Single phase supply on smaller units, control wiring where specified |
| Installation format | Wall mounted or skid mounted, fixed or portable |
